It is well known in the art that a gear type transmission may be used for running a motor vehicle, motorcycle or the like. However, gear type transmissions have a fixed number of gears. They are generally designed to operate most efficiently in one of the gears, leaving the others to cause the engine to run at less efficient operating points. Consequently, for the purpose of improving efficiency a continuously variable transmission, CVT, is preferable. Various types of belts have been developed for use in continuously variable transmissions.
Generally, the CVT belts have a silhouette similar to that of a conventional V-belt. In particular, they are broad at the top and narrow at the bottom and designed to fit between the sheaves of a pulley, the pulley defining an angular groove. The pulley on which the belt is trained comprises a moveable sheave and a fixed sheave, both having a truncated cone shape. Generally, one of the sheaves moves while the other remains fixed.
Moving one sheave in relation to the other effectively varies the effective diameter .phi. of the pulley within which the belt operates. Consequently, belt speed is a function of the effective diameter of the pulley, which is in turn a function of the axial position of the sheaves relative to each other.
CVT belts in the prior art include belts comprising a plurality of blocks mounted transversely on a tensile member as well as monolithic metal belts. Certain forms of cog type belts are also known.
Representative of the art is the belt disclosed in U.S. Pat. No. 5,147,253 to Douhairet et al. Disclosed is a CVT belt comprising a plurality of transverse links arranged about an endless core. The endless core comprises a v belt. The v belt has oblique walls in contact with the interior surfaces of the links. The exterior oblique surfaces of the links are in contact with the flanges of the transmission pulleys. This device is only suitable for use with v belts, which have relatively low power transmission capabilities. Further, each link is constructed such that the v belt does not bear on the bottom of each link. Therefore, the v belt will be pressed into the bottom of the link when the belt is under load. This will change the pitch line diameter of the belt, resulting in an improper fit between the belt and the pulley and premature failure.
Also representative of the art is U.S. Pat. No. 5,242,332 to Douhairet et al. Disclosed is a CVT belt comprising a plurality of transverse links arranged about an endless core. Each link includes a strap, thereby making each link closeable as a means for connecting a link to the endless core. The strap is a cumbersome addition to the belt which adds weight. Weight serves to limit the operational limits of the belt. The endless core comprises a v belt. The v belt has oblique walls in contact with the interior surfaces of the links. The exterior oblique surfaces of the links are in contact with the flanges of the transmission pulleys.
In the prior art belts, the core member belt is captive within the clips or blocks so it cannot be replaced in the event of wear or failure. The core member belt is an integral part of the belt. Core failure obliges the user to replace the entire belt.
What is needed is a multi-ribbed CVT belt having a multi-ribbed belt core. What is needed is a multi-ribbed CVT belt having a plurality of cooperating transverse clips that have a conjugate shaped surface to engage the multi-ribbed core. What is needed is a multi-ribbed CVT belt having plastic transverse clips. What is needed is a multi-ribbed CVT belt having metal overmolded transverse clips. What is needed is a multi-ribbed CVT belt having a core member comprising a readily available belt. What is needed is a multi-ribbed CVT belt having a core belt that is easily replaced. The present invention meets these needs.